Hoist motor and brake control



Feb. 18, 1958 2 Sheets-Sheet. 1

Filed Feb. 28, 1955 8 m w 5 mm m 5 4 m w a 5 mm E R 4 I u U V 8 i m 2 aKZL 4m I ATTORNEYS United States Patent f HOIST MOTOR AND BRAKE CONTROLRobert E. Zwayer, Bryan, Ohio, assignor to ARO Equipment Corporation,Bryan, Ohio, a corporation of Ohio Application February 28, 1955, SerialNo. 490,968

9 Claims. (Cl. 192-3) This invention relates generally to a controlvalve for hoists and the like.

It is a primary object of this invention to provide a balanced pneumaticvalve capable of performing both throttling and reversing functions incooperative relation with a reversible pneumatic motor.

It is another object of this invention to provide a balanced valve ofspecial construction wherein a plunger is reciprocably movable in a boreand carries a pair of valve heads spaced relative to the length of thebore to effect selective opening and closing of the ends thereof, saidborehaving particularly positioned intake and exhaust ports regulated bymovement of said plunger for controlling the operation of a reversibleair motor.

It is a further object to provide a control valve of the type aforesaid,wherein actuating means for reciprocating the plunger operativelycooperates with braking means for the reversible air motor, the valveheads and the intake and exhaust ports being precisely located forachieving accurate timing between the operation of the motor and thebrake.

It is another object to provide a control valve for an air motor drivenhoist, wherein smooth performance is achieved during load lowering bymeans of a novel porting arrangement serving to dissipate a substantialportion of the energy developed by the descending load through the motoras compressed air rather than through brake means as heat.

It is a still further object to provide a control valve for a reversibleair motor of a power driven hoist having brake means operativelyassociated therewith, wherein selective speed control may be achievedduring load lowering by means of (1) the brake, (2) operation of themotor as an energy-consuming pump by compression of exhaust air, and (3)positive motor drive.

it is still another object to provide an air motor driven hoist havingspring loaded brake means, wherein low resistance at the controls isoffered to the operator through the use of a single balanced controlvalve, the force due to air pressure at one end of the valve beingbalanced by an equal and opposite force from air pressure at the otherend of the valve, thereby permitting the operator to effect manualoperation against the force of the brake spring only.

With these and other objects in view, my invention consists in theconstruction, arrangement, and combination of the various parts of mycontrol valve for hoists and the like, whereby the objects contemplatedare attained, as hereinafter more fully set forth, pointed out in myclaims and illustrated in the accompanying drawing, wherein:

Figure l is aside elevational view, partly in perspective, showing apneumatic hoist embodying the valve construction of the presentinvention;

Figure 2 is an enlarged vertical sectional view taken substantially asshown at 2-2 on Figure 1, showing the operating control in a neutralposition and the motor brakeapplied; v

Figure 3 is a fragmentary vertical sectional view, on

2,823,775 Patented Feb. 18, 1958 an enlarged scale, taken through theright hand end of the hoist of Figure 1;

Figure 4 is a diagrammatic view of the pneumatic motor and related valveporting, showing the cooperation thereof with the valve of thisinvention;

Figure 5 is a vertical sectional view taken substantially as shown atline 55 on Figure 3, showing the valve in a neutral position;

Figure 6 is a sectional view similar to Figure 5, showing the valve inan operating position for elevating a load;

Figure 7 is a fragmentary view similar to Figure 2 showing the motorbrake in an applied position just prior to release;

Figure 8 is another sectional view similar to Figure 5, showing thevalve in an operating positon for lowering a load;

Figure 9 is another fragmentary view similar to Figure 7, showing thebrake in a disengaged position;

' Figure 10 is a sectional view similar to Figure 8, show ing the valvein operating position for lowering a load at a more rapid rate.

Referring now to the accompanying drawing, I have used the referencenumeral 10 to indicate a hoist housing. As indicated diagrammatically inFigure 4, the housing 10 provides a stator 12 and a rotor 14 which ismounted on a motor shaft 16. The rotor 14 is provided with a pluralityof vane slots 17 which receive radially slidable vanes 18. The vanes 18move outwardly in their slots in response to centrifugal force when therotor 14 is driven, and contactingly engage the inner surface of thestator 12. The rotor 16 is eccentrically positioned relative to thestator 12, in the conventional manner of pneumatic motor constructions.

A sprocket and suitable step-down gearing, not illustrated herein butshown and described in co-pending Shatf application, Serial No. 381,319,filed September 21, 1953, having a common assignee with the presentinvention, serve to raise and lower a chain 26 as the motor rotor 14rotates in one direction or the other. A suspending hook 22 and a chainhook 24 are connected in the usual manner with the housing 10 and thechain 20, respectively, as shown in Figure 1.

A cover plate 26 is provided over the right hand end of the housing 10,as viewed in Figure 1. The plate 26 forms a bore 28 therein, in which ispositioned a sleeve 30. A pair of plugs 32 (see Figure 5) arescrew-threadedly received within the cover plate 26 at opposite ends ofthe bore 28.

The plate 26 is provided with a compressed air inlet fitting 34 which isadapted to be connected to a suitable source of air under pressure. Theinlet 34 communicates with an intake passageway 36, having its endportions 38 and 39 terminating at the opposite ends of the bore 28.

A pair of intake ports 40 and 42 (see Figure 5) communicate through thesleeve 30 with a pair of flow conduits 44 and 46, respectively, asindicated diagrammatically in Figure 4. The conduits 44 and 46 lead toopposite sides of the hoist motor. A pair of exhaust ports 48 and 50(see Figure 5) communicate through the sleeve 30 with the bore 28. Theexhaust ports 48 and 50 are connected by a passageway 52 (see Figure 3)to a cavity 54 in the bottom of the motor stator 12. The cavity 54communicates with a passageway, not shown, around the stator to aplurality of discharge ports for exhaust to the atmosphere at 57 (seeFigure 3), in conventional manner. In addition, primary exhaust ports,indicated diagrammatically in Figure 4 at 56, provide communication fromthe top of the stator to atmosphere through 57. A similar portingarrangement of this same general type is shown and described inco-pending Shaft application, Serial No. 381,319, filed September 21,

'aseexzvs 1953, having a common assignee with the present invention.

A plunger 60 is slidable in the sleeve 30, and serves to selectivelycover the exhaust ports 48 and 50.- Stem portions 62 and 64 extend fromthe ends of the plunger and terminate in heads 66 and 68. Sealing rings70 and 72 carried by the heads 66 and 68 contactingly engage the innerwall of sleeve 30.

The bottom of the plunger 60 is provided with rack teeth 74 which meshwith a pinion 76 journaled on a pin 78. A gear sector 80 is mounted on arock shaft 82 which is connected to a control lever 84. Flexibleelements 86 and 88- are suspended from the ends of the lever 84- forrocking the shaft 82.

In Figure 2, I have illustrated a brake drum 90 which is rotatablycarried by the motor shaft 16. A pair of brake shoes 92 and 94 ofsemi-cylindrical form are pivotally secured at their upper ends to afixed support member 96. A pair of fiber brake liners 98 are carried bythe brake :shoes 92 and 94. A resilient loading clamp 100 serves to biasthe brake shoes 92 and 94 inwardly toward the brake drum 90 so as toeffect tight contacting engagement between the brake liners 98 and theouter surface of the brake drum 90.

An actuator element 102 is carried by the rock shaft 82, and whenrotated thereby to the positions illustrated in Figures 7 and 9, servesto engage downwardly extending portions of the brake shoes 92 and 94 forseparating them against the biasing force of the clamp 100. The rockshaft 82 is normally centered, as seen in Fig ure 2, by means of thebent lower ends of the brake shoes 92 and 94 pressing against the flatsides of the actuator element v102 due to the force exerted by theresilient loading clamp 100. The arrangement of parts for the centerposition of the rock shaft 82 is shown in Figure 5.

The practical operation of the hoist valve construction disclosed by thepresent invention will best be described by reference to Figures throughof the drawing. In Figure 5, the plunger 60 is shown in its neutralposition slightly off center relative to the ends of the sleeve 30. Asshown, the exhaust port 48 is completely closed by the valve plunger 60,and :the exhaust port 50 is substantially fully closed but cracked opena very slight amount. The valve heads 66 and 68 serve to effect closureof both ends of the sleeve 30. A flow of compressed air from the inlet34 into the sleeve .30 is thereby prevented, and no air is supplied to.the intake ports 40 and 42. It should be noted thatalthough the plunger60 is disposed slightly off center, the control lever 84 andthe gearsector 80 regulated thereby are balanced in a center position.

In Figure .6, theplunger 68 is shown inashifted position toward theleft. This movement .is effected when the operator pulls down -on.theflexible element 86 a slight distance to rotate the rock shaft-82 in aclockwise direction as seen in Figure .6. The pinion 76 is rotated in acounter-clockwise direction,.and .the :plunger :60 .is moved to theleft. The head '66 no longer effects closure of the sleeve end, andcompressed air flow will enter the sleeve 30 and pass through the intakeport 40, and -.c0nduit 44 to the air motor. This will effect forwarddrive of the motor and a load-secured'to the chain hook 24. willbeelevated.

It is important to notezthat load elevation will'occur in this mannerbefore thebrake has lbeenreleased, thereby preventing a risk of loadslippage before ssufi'icient power is provided by the air motor.

As clearly'indicated inFigure 4 .of the drawing, v.the' flow pattern isfrom air-entry at intake port 40 tohirexhaust at port 42, which now actsas .ancxhaustport; The exhaustvport 50 is, of course, now fully opento,complete the exhaust fiowfrom the portal 'The exhaust port 48 isfully-closed. 3

In Figure 7 of the drawing, the corresponding brake operation is shownfor comparison with the simultaneous operative positioning of thecontrol valve. As shown, the brake shoes 92 and 94 are about to bereleased from the brake drum by the actuator element 102, which isrotated by the rock shaft 82. It will be apparent that when the operatorpulls theflexible element 86 further downward, the brake will bereleased, the valve head 66 will be moved to permit maximum air supplyto the sleeve 30, and the motor will impart full power for effectingload elevation.

In Figure 8 of the drawing, I have Shown the relationv ship of parts foreifecting load lowering. The operator has drawn the flexible element 88downwardly a slight amount, effecting rotation of the rock shaft 82 andconsequent shifting of the plunger 60 to the right. As shown, both ofthe valve heads 66 and 68, although moved beyond the centered closureposition of the plunger, still eifect flow closure of both ends of thesleeve 30. No air is admitted to the motor. It should be noted that bothof the exhaust ports 48 and are fully closed by the valve plunger 60.

As seen in Figure 9 of the drawing, the brake will at this time begin tobe released by the actuator element 102, and the load will be permittedto descend slowly under brake speed regulation only. The :descendingload now runs the motor as a pump, and the compression of exhaust airdissipates a greater part of the energy developed by the descending loadthrough the motor rather than through the brake as mechanicallygenerated heat. The load may thereby descend at a slow rate of descentby the combined opposing forces exerted by the brake and the motoroperating as a pump.

In order to increase the rate of load descent, the operator pulls downon the flexible element 88 so as to further rotate the rock shaft 82 andmove the valve plunger further to the right to the position shown inFigure 10. The exhaust port 48 is now slightly cracked open, therebyreducing the resistance or pump elfect of the motor, and permitting amore rapid lowering of the load. As the valve plunger is moved stillfurther toward the right, the exhaust port 48 will be opened more fully,and the lowering speed correspondingly increased as the motor offersstill less resistance through compression of exhaust air. When theplunger 60 has been moved sufficientlyfar to the right to permit thevalve head 68 to open the end of the sleeve 30, compressed air will befed to the motor through the intake port -42 thereby driving the loaddown.

It will be apparentrthat I have providedbythe present invention abalanced control valve .cornbiningthrottling and reversing functions incooperation witha reversible air motor having mechanicallybraking meansassociated therewith. Byprecisely locating the valve heads, and theintake and exhaust ports, to achieve accurate timing between the motorand the brake, I provide smooth load elevation without risk of slippageatlow motor power..

Further, efiective speed control is achieved during load loweringthroughmechanical braking, exhaust air compression or pump action by themotor, and positive motor drive.

Changesmay be made .in theconstruction and arrangement of the parts ofmy control valve for hoists and the.

compressed air communicating with said bore at the 0ppo-' site openendsthereoflaplunger reciprocably slidable in said bore and carrying apair of valve'heads spaced relative to the length of said bore so as toeffect selective opening and closing of the ends of said bore whenreciprocated, means for reciprocating said plunger in said bore, saidbody providing a pair of intake ports communicating with said bore andadapted to transmit a flow of compressed air from said bore to theforward and reverse *actuating sides respectively of said reversible airmotor, and said body providing a pair of exhaust ports communicatingwith said bore and through said bore one with a forward and the otherwith a reverse intake port, said plunger serving to selectively closedand open said exhaust ports when reciprocated, whereby upon movement ofsaid plunger in one direction or the other to open alternatively theends of said bore and supply compressed air to a corresponding intakeport, said exhaust ports will be opened :and closed by said plunger in aselective manner for operation of said air motor as a pump when drivenin a reverse direction.

2. In combination with a reversible air motor having a source ofcompressed air, a valve structure comprising a valve body forming anopen-ended bore, said source of compressed air communicating with saidbore at the opposite open ends thereof, a plunger reciprocably slidablein said bore and carrying a pair of valve heads spaced relative to thelength of said bore so as to effect selective opening and closing of theends of said bore when reciprocated, means for reciprocating saidplunger in said bore, said body providing intake ports communicatingwith said bore and adapted to transmit a flow of compressed air fromsaid bore to the forward and reverse actuating sides respectively ofsaid reversible air motor, said body providing exhaust portscommunicating with said bore and through said bore with correspondingforward and reverse intake ports, said plunger serving to selectivelyclose and open said exhaust ports when reciprocated for effectingthrottling of said air motor, and brake means operatively associatedwith said reversible air motor for effecting speed regulation thereof,said plunger reciproeating means also serving to operatively regulatesaid brake means, thereby permitting cooperative timing of said airmotor and brake means.

3. In combination with a reversible air motor having a source ofcompressed air, a valve structure comprising a valve body forming anopen-ended bore, said source of compressed air communicating with saidbore at the opposite open ends thereof, a plunger reciprocably slidablein said bore and carrying a pair of valve heads spaced relative to thelength of said bore so as to effect selective opening and closing of theends of said bore when reciprocated, said body providing intake portscommunicating with said bore and adapted to transmit a flow ofcompressed air from said bore to the forward and reverse actuating sidesrespectively of said reversible air motor, said body providing exhaustports communicating with said bore and through said bore withcorresponding forward and reverse intake ports, said plunger serving toselectively close and open said exhaust ports when reciprocated foreffecting throttling of said air motor, brake means operativelyassociated with said reversible air motor in normally engaged relationfor effecting speed regulation thereof, and actuator means operativeboth to reciprocate said plunger and to disengage said brake means,thereby permitting cooperative timing of said air motor and brake means.

4. In combination with a reversible air motor having a source ofcompressed air, a valve structure comprising a valve body forming anopen-ended bore, said source of compressed air communicating with saidbore at the opposite open ends thereof, a plunger reciprocably slidablein said bore and carrying a pair of valve heads spaced 7 relative to thelength of said bore so as to effect selective opening and closing of theends of said bore when reciprocated, said body providing intake portscommunieating with said bore and adapted to transmit a flow ofcompressed air from said bore to the forward and reverse actuating sidesrespectively of said reversible air motor, said body providing exhaustports communicating with said bore and through said bore withcorresponding forward and reverse intake ports, said plunger serving toselectively close and open said exhaust ports when reciprocated foreffecting throttling of said air motor, brake means operativelyassociated with said reversible air motor in normally engaged relationfor effecting speed regulation thereof, and actuator means operativeboth to reciprocate said plunger and to disengage said brake means,whereby reciprocation of said plunger to effect air throttling andreversing of said motor also serves to effect predetermined cooperativeregulation of the braking of said motor in accurately timed sequencetherewith.

5. In combination with a reversible air motor having a source ofcompressed air, a valve structure comprising a valve body forming anopen-ended bore, said source of compressed air communicating with saidbore at the opposite open ends thereof, a plunger reciprocably slidablein said bore and carrying a pair of valve heads spaced relative to thelength of said bore so as to effect selective opening and closing of theends of said bore when reciprocated, said body providing a pair ofintake ports communicating with said bore and adapted to transmit a flowof compressed air from said bore to the forward and reverse actuatingsides respectively of said reversible air motor, said body providing apair of exhaust ports intermediate said intake ports and communicatingwith said bore and through said bore one with a forward and the otherwith a reverse intake port, said plunger serving to selectively closeand open said exhaust ports when.

regulation thereof, and actuator means operative both to reciprocatesaid plunger and to disengage said brake means, whereby reciprocation ofsaid plunger to effect air throttling and reversing of said motor alsoserves to effect predetermined cooperative regulation of the braking ofsaid motor in accurately timed sequence therewith.

6. In combination with a reversible air motor having a source ofcompressed air, a valve structure comprising a valve body forming anopen-ended bore, said source of compressed air communicating with saidbore at the opposite open ends thereof, a plunger reciprocably slidablein said bore and carrying a pair of valve heads spaced relative to thelength of said bore so as to effect closure of the ends of said borewhen said plunger is disposed in a slightly off-center neutral position,means for reciprocating said plunger in said bore, said body providing apair of spaced intake ports communicating with said bore and adapted totransmit a flow of compressed air from said bore to the forward andreverse actuating sides respectively of said reversible air motor, saidbody providing a pair of spaced exhaust ports intermediate said intakeports and communicating with said bore, each of said exhaust ports whenopen communicating through said bore with a corresponding one of saidintake ports, said plunger serving to completely close one of saidexhaust ports and crack open the other of said exhaust ports a veryslight amount when in neutral position, and serving to selectively closeand open said exhaust ports when reciprocated; whereby upon movement ofsaid plunger in one direction from its neutral position to open one endof said bore and supply compressed air to the forward intake port, saidclosed exhaust port will remain closed and said slightly open exhaustport will be fully opened, thereby providing full forward driving powerto said motor; and whereby upon movement of said plunger in the otherdirection from its neutral position to open the other end of said boreand supply compressed air to the reverse intake port, both of saidexhaust ports will first be closed and one of said exhaust portsthereafter progressively opened, thereby 7 effecting variable operationof said motor as a pump to compress exhaust air.

7; In combination with a reversible air motor havinga source ofcompressedair; a valve structure comprising a valve body forming anopen-ended bore, said source ofcompressed air communicating with saidbore. at the opposite open endsthereof, a plunger reciprocably slid ableinsaid bore and carrying apair of valve heads spaced relative to thelength of said bore so as to efiect closure of the ends: of saidherewhen said plunger is disposed'i'n a slightly off-center neutralposition, said body providing a pair of spaced intakeports communieatingwith said bore and adapted to transmit a How ofcompressed air from saidbore to the forward and reverse actuating; sides respectively of saidreversible air motor, said body providing a pairof spaced exhaustportsintermediate saidintakeports and communicating with said here, each ofsaid exhaust ports.v when open communicating through said" borewith acorresponding one of said intakeports, said plunger serving tocompletely close one of said exhaust ports andtcrackopen the other ofsaid exhaust ports a very slight amount when in neutral position, andserving to selectively close and open said exhaust ports whenreciprocated; whereby upon movement ofv said plunger in one directionfrom its neutral position to open one-end of said bore and supplycompressed air to the forward intake port, said closed exhaust portwill: remain closed and said slightly open exhaust. port will befullyopened, thereby providing full forward driving power'to said'motorgand whereby upon movement; of said. plunger in the other directionfrom itsneutral position to open the other end of said bore and supplycompressed airto the reverse intake port, both of said: exhaust portswill first beclosed' and one of said exhaust: ports thereafterprogressively opened, thereby effecting variable. operation of saidmotor as a pump to compress exhaust air; brake means operativelyassociated with. said reversible air motor in normally engaged relationfor effecting. speed. regulation thereof; and actuator means, operativeboth to reciprocate said plunger and. to, disengage saidtbrake means,whereby reciprocationofsaidi plunger'to effect air throttling and:reversing? of said motor'also serves to eifect predeterminedcooper-ative regulation of the braking ofi said=- motor inaccurately" nationwith'a reversible air motor of the type having" brake means operativel'yassociated therewith, said valve comprisinga balanced reciprocableplunger operative toeflect selective:v porting of compressed air forcombined reversing and throttling of said airmotor, and actuator meansoperative bothtoreciprocate said plunger and to regulate said brakemeans, whereby speed control may be achieved-selectively'by means ofsaidbrake, by operation ofsaid airmotor as-an energy-consuming pump, and bypositive drivingoperation of said motor.

9. 111a hoist construction, a control valve in combine tion withareversibleairmotor ofthe type having brake means operatively associatedtherewith, saidvalve comprising an air pressure balanced reciprocableplunger operativete'efiect selective porting of compressed air forcombined' reversing and throttling of said air motor, forward motoroperation serving to effect load elevating operation of said-hoist andreverse operation of saidair motor serving to effect load loweringoperation of said hoist, and actuator means operative both toreciprocate References Cited in the file of this patent UNITED STATES iPATENTS 583,822 Shem, -N June 1, 1897' 2,4011258' Livers, Mar. 28*;1'9462,4455'8'5) Shaft u July 20, 1948 2,694,384 Evans Nov. 16, 1954' ,7Q2;09 e lQff --.--r--,-- 15;.

